Contribution of MX dynamin, oligoadenylate synthetase, and protein kinase R to anti-paramyxovirus activity of type 1 interferons in vitro

Abstract

Objective - To determine the contribution of MX dynamin, oligoadenylate synthetase (OAS), and double-stranded RNA-dependent protein kinase R (PKR) to the antiviral effects of type 1 interferons (IFNs) against bovine parainfluenza-3 virus (PI-3V) infection of Vero cells. Sample Population - Vero cell cultures. Procedures - PI-3V yield was first compared between control and transfected type 1 IFNs-incompetent Vero cells expressing recombinant OAS or MX proteins. Afterwards, phosphorylation of eukaryotic initiation factor 2 α (eIF2α) was used to scale the degree of PKR activation upon infection of Vero cells by PI-3V. Results - Overexpression of OAS did not result in significantly decreased viral replication. Phosphorylated eIF2α forms, the hallmark of PKR activation, were not increased in IFNα-primed infected Vero cells. Although human MXA contributed to partial blockade of replication of bovine PI-3V, the antiviral effect was not as strong as that of IFNα. Conclusions and Clinical Relevance - The powerful anti-Paramyxovirus activity of type 1 IFNs is mediated by noncanonic pathways.